Neuropharmacological effects of extracts from Sickingia williamsii.

Sickingia williamsii Standl. (Rubiaceae) is used in Peruvian folk medicine for its analgesic and anti-inflammatory activity. In this study we have examined the pharmacological profiles of petroleum ether, chloroform, chloroform-methanol (9:1) and methanol extracts of the tree. Both chloroform-methanol (250, 500 or 750 mg kg-1, p.o.) and methanol (125, 250 or 500 mg kg-1, p.o.) extracts significantly reduced both the locomotor activity and motor co-ordination of mice; they also prolonged sleep induced by pentobarbital, although no significant cataleptic response was observed. These extracts did not have a significant impact on the nociceptive threshold in the hot-plate and tail-flick tests. Petroleum ether and chloroform extracts did not, furthermore, induce any significant pharmacological effects. The results of the study suggest that these extracts possess neurosedative-like properties.